The present invention relates to a seal for a rotating shaft, more specifically an integrated seal for a gas turbine engine shaft.
Frequently in gas turbine engines, it is necessary to pass a rotating shaft through a stationary partition wall forming part of an enclosure, one of which contains air and oil on one side of the partition and the other of which holds air on the opposite side of the partition which must be kept free of oil. It has proven difficult to provide a seal around the shaft passing through the partition which will effectively prevent the intermixing of the elements on opposite sides of the partition wall.
European patent application 0 110 804 discloses a rotating seal arrangement wherein a circular shaped seal element is fixedly secured to a rotating shaft and is used in combination with a valve element to prevent the escape of oil from the lubricated seal.
French Patent 2,120,656 discloses, in FIG. 2, a carbon ring held around a shaft by means of a circumferential spring extending around the carbon ring. The ring is placed within a cage wherein it is positioned relative to a retaining ring by a spring means.
Other solutions to this problem have involved the mounting of a case with a de-oiling coil near where the shaft passes through the partition. These solutions may or may not include a segmented ring which is directly mounted and preassembled on the case. While these solutions had made the implementation easier, they entail the drawback of increased weight and higher costs.